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  • 1
    Electronic Resource
    Electronic Resource
    Raman study on molecular motion in tetramethylammonium hydroxide pentahydrate (1991)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 95 (1991), S. 8693-8696 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The Raman spectrum as well as conductivity and differential-thermal-analysis (DTA) thermogram of tetramethylammonium hydroxide pentahydrate was observed at various temperatures in order to investigate molecular motion in relation to conductivity and a phase transition. It was clarified that different stepwise protonation processes become effective for relaxation in the O–H stretching of hydroxide ions as temperature is increased. The activation energy was 6.1 and 16.0 kJ/mol in 130≤T〈210 and 210≤T≤250 K, respectively, whereas the activation energy in conductivity was 41.1 kJ/mol below 250 K. This discrepancy was discussed according to a reorientational motion of water molecules. The Raman band shape of the NM4 asymmetric stretching of tetramethylammonium ions was analyzed on the basis of the reorientational motion about the C3 and C2 axes on the ion, and the activation energies were 8.7 kJ/mol (about the C3 axis) and 14.5 kJ/mol (about the C2 axis).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.461254
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  • 2
    Electronic Resource
    Electronic Resource
    Hydrogen Storage Properties of Mg-Al Alloy Prepared by Super Lamination Technique (2007)
    s.l. ; Stafa-Zurich, Switzerland
    Advanced materials research Vol. 26-28 (Oct. 2007), p. 857-860 
    Details
    ISSN: 1662-8985
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Microstructures and hydrogen storage properties of Mg-Al super laminate compositealloys were investigated. The laminated sample was made by alternately stacking Mg films and Alfilms. The laminate was subjected to repetition of stacking and cold-rolling under an ambientcondition (super lamination technique), combined with final heat treatment under an argon gasatmosphere. The number of films and thickness was nearly 15000 layers and about 50μm,respectivery. Their microstructures and hydrogen storage properties were studied by scanningelectron microscopy, X-ray diffractometry and volumetric method by use of a Sieverts-typeapparatus. In heat treatment process at 673K, Mg17Al12 intermetallic compound was formed byinterdiffusion. This compound absorbed and desorbed hydrogen reversibly through thedisproportionation and recombination react at 673K
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/01/40/transtech_doi~10.4028%252Fwww.scientific.net%252FAMR.26-28.857.pdf
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  • 3
    Electronic Resource
    Electronic Resource
    Hydrogenation Characteristics of Mg Based Alloy Prepared by Super Lamination Technique (2007)
    s.l. ; Stafa-Zurich, Switzerland
    Materials science forum Vol. 561-565 (Oct. 2007), p. 1609-1612 
    Details
    ISSN: 1662-9752
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: In order to improve the hydrogenation property of Mg/Ti laminate composite, Ni wasadded as a third element. Hydrogen storage properties of the laminated Mg/Ti/Ni alloy films werestudied. Laminated Mg/Ti/Ni multilayer alloy films were prepared by cold rolling of stacked Mg,Ti and Ni under ambient conditions. The stacked foils were subjected to repetition of rolling andstacking, resulting in super-laminated foils with the thickness less than 0.3mm, containing morethan 15000 layers. Microstructures of the super-laminates were studied by scanning electronmicroscopy and X-ray diffractometry. Their hydrogenation behaviors were investigated by use of aSieverts type apparatus. The hydrogen storage capacity (H/M) of the laminate with compositionMg/Ti/Ni=9.0/0.9/0.1 amounted H/M=1.6 at 573K, 0.4MPa. Initial activation property wasimproved by controlling the amount of Ni appropreately
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/02/18/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.561-565.1609.pdf
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  • 4
    Electronic Resource
    Electronic Resource
    Comparison between Mg/Cu Super-Laminates and Mg〈sub〉2〈/sub〉Cu Powder in Microstructure and Hydrogen Storage Properties (2007)
    s.l. ; Stafa-Zurich, Switzerland
    Materials science forum Vol. 561-565 (Oct. 2007), p. 1581-1584 
    Details
    ISSN: 1662-9752
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Super-laminates have been attracting attention since co-authors Ueda et al. reported thatMg/Cu super-laminates showed reversible hydrogenation and dehydrogenation at 473K. TheMg/Cu super-laminates were prepared by a repetitive fold and roll method. Initial activation at 573K led the super-laminates to absorb hydrogen at 473K. TEM observations of micro/nano-structuresin the super-laminates and Mg2Cu powder were performed in order to clarify the process ofhydrogenation and dehydrogenation at 473K. The as-rolled Mg/Cu super-laminates have laminatedstructures in size of sub-micrometer thickness composed of Mg and Cu layers with dense latticedefects. The super-laminates after initial activation keep laminated structure and have uniformlydistributed pores with a sub-micrometer diameter. It is considered that these micro/nano-structuresof Mg/Cu super-laminates lead to lower dehydrogenation temperature and better kinetics
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/02/18/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.561-565.1581.pdf
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  • 5
    Electronic Resource
    Electronic Resource
    Phase Transition of Mg/Pd Laminate Composites during Hydrogenation/Dehydrogenation (2007)
    s.l. ; Stafa-Zurich, Switzerland
    Materials science forum Vol. 561-565 (Oct. 2007), p. 1593-1596 
    Details
    ISSN: 1662-9752
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Mg-based laminate composites prepared by a repetitive-rolling method have a largehydrogen capacity as well as good kinetics and reversibility for hydrogen reaction. Mg/Pd laminatecomposite (Mg/Pd=6) can absorb a large amount of hydrogen up to 1.47 H/M (4 mass%), and desorbhydrogen reversibly at 573K. In this study, we investigated the mechanism of phase transition of theMg/Pd laminate composites during hydrogenation/dehydrogenation by means of in-situ XRDmeasurements. In Mg/Pd laminate composite (Mg/Pd=6), the XRD profile of as-rolled sample indicatedthe existence of Mg and Pd within the detection ability of our XRD equipment. Mg6Pd intermetalliccompound are formed during initial activation process. The Mg6Pd intermetallic compound can storehydrogen reversibly through the disproportionation and recombination processes
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/02/18/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.561-565.1593.pdf
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  • 6
    Electronic Resource
    Electronic Resource
    Effect of alloying element content on ion-nitriding behavior of Fe-Ti alloys (1986)
    Springer
    Oxidation of metals 26 (1986), S. 19-31 
    Details
    ISSN: 1573-4889
    Keywords: ion-nitriding ; Fe-Ti alloys ; diffusion coefficient of nitrogen ; hardness ; TiN,y′-Fe 4 N
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The ion-nitriding behavior of iron alloys with a titanium content of between 1.07 and 2.58 wt.% was investigated in the α-phase region. The behavior was found to be analogous to the internal oxidation behavior of iron alloys: An internal-nitriding layer, where small TiN precipitates are dispersed, as well as a very thin surface layer of γ′-Fe4N were formed. A parabolic rate law holds for growth of the internal-nitriding layer. The kinetics of growth of the internalnitriding layer is discussed according to the rate equation of internal-oxidation, giving the diffusion coefficient of nitrogen, D N app , in the layer. The measured D N app decreases as the volume fraction of TiN, f, increases, indicating that the diffusion of nitrogen is apparently inhibited by the existence of TiN precipitates. Furthermore, the diffusion coefficient of nitrogen in α-iron was evaluated by extrapolating D N app to f=0, being in good agreement with that reported previously. The f-dependence of D N app is discussed in terms of the effective area for diffusion of nitrogen in α-iron.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00664271
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  • 7
    Electronic Resource
    Electronic Resource
    Ion-nitriding of an Fe-19 wt % Cr alloy (1986)
    Springer
    Journal of materials science 21 (1986), S. 2493-2496 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The ion-nitriding behaviour of an Fe-18.75wt% Cr alloy was investigated at 803 K under constant plasma conditions. Both a thin surface layer ofγ′-Fe4N and an internal-nitriding layer were observed. The nitride formed in the internal-nitriding layer was found to be CrN, rather than Cr2N. The hardness of the nitriding layer rises to Hv=1200 due to small CrN precipitates. The growth rate of the internal nitriding layer, in the present alloy is controlled by a nitrogen diffusion process in the matrix metal,α-iron. Because such ion-nitriding behaviour is analogous to that of internal-oxidation, the growth rate of nitriding was discussed according to the rate equation to that of internal-oxidation. The nitrogen diffusion in the present alloy is scarcely affected by the CrN precipitates.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01114296
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  • 8
    Electronic Resource
    Electronic Resource
    Ion-nitriding behaviour of Fe-Ti alloys in theα-phase region (1986)
    Springer
    Journal of materials science 21 (1986), S. 2514-2518 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The ion-nitriding behaviour of four iron alloys containing between 0.11 and 1.48 wt% titanium was investigated in theα-phase region to discuss kinetics of the growth of the nitriding layer. The ion-nitriding experiments have been made at 823 K. Two nitriding layers were observed: a thin surface layer which mainly consists of Fe4N; an internal nitriding layer beneath the surface layer, where the nitride formed was found to be TiN. The growth of the internal nitriding layer is controlled by a diffusion process of nitrogen in the matrix metal. The apparent diffusion coefficient of nitrogen in the nitriding layer, evaluated using the rate equation proposed for internal oxidation, increases linearly with the volume fraction of titanium nitride. Furthermore, by excluding the effect of the titanium nitride from the apparent diffusion coefficient, the diffusion coefficient of nitrogen inα-iron was calculated, being in good agreement with that reported so far. In addition, the increase in hardness in the internal nitriding layer has been discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01114299
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